need help with 6 and 7 show work please Susan drove 1500 miles to Phoenix for sp
ID: 2892683 • Letter: N
Question
need help with 6 and 7 show work please Susan drove 1500 miles to Phoenix for spring break. On the way back she averaged 10 miles per hour less, and the drive back took per 5 hours longer. Find Susan's average speed each way (to and from Phoenix) The Empire State Building is 1250 feet tall. If an object is thrown upward from the top of the building at an initial velocity of 38 feet per second, its height s seconds after it is thrown is given by the function h(s) = -16s^2 + 38s +1250 a. How long after the hall is tossed is It 288 feet from the ground? b. What is the maximum height the hall will reach? c. After how many seconds will the ban hat the ground? Find all solutions: 3t^2 - 1 = 2t + S.Explanation / Answer
7.
height function is given by:
h(s) = -16s^2 + 38s + 1250
A.
h(s) = 288 = -16s^2 + 38s + 1250
16s^2 - 38s - 962 = 0
Solving the qudratic equation:
s = [38 +/- sqrt (38^2 + 4*16*962)]/32
s1 = 9.03 sec And s2 = -6.66 sec
Since time cannot be negative, so height will be 288 m after 9.03 sec
B.
At max height speed is zero,
v = dh/ds = 0
v = d(-16s^2 + 38s + 1250)/ds
v = -32*s + 38
v = 0, when
38 - 32s = 0
s = 38/32 = 1.1875 sec
at this time height will be
h(s) = -16*1.1875^2 + 38*1.875 + 1250 = 1298.69 m
C.
ball will reach to the when
h(s) = 0
-16s^2 + 38s + 1250 = 0
solving the qudratic equation:
s = [- 38 +/- sqrt (38^2 + 4*16*1250)]/(-32)
s = 10.11 sec
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